During fuel cell operation, byproducts such as product water and nitrogen, as well as unconsumed hydrogen, may form at the anode side of a fuel cell stack. In certain known systems, accumulation of product water and nitrogen accumulation is controlled in an attempt to avoid a reduction in fuel cell performance, and/or fuel cell system shut down. One known approach is to release the water and nitrogen via a passageway downstream of the fuel cell stack. Using such approach, the passageway is coupled with a valve for the controllable release of water and nitrogen from the fuel cell stack. This approach causes the potential for problems to occur during cold weather operation of the fuel cell when water may freeze in the passageway, or valve, or other regions of the fuel cell with small cross sectional areas. The resulting ice formation may cause blockage of at least a portion of the passageway and prevent fluid flow (e.g., water and nitrogen removal), which may inhibit fuel cell system function.
To avoid the blockage of fuel cell knock out drain under cold ambient condition, various methods have been employed with additional hardware. For example, a “scavenging reservoir” may be employed to provide an open passage adjacent to ice. However, in many instances, the increased volume of the water due to freezing may cause a complete blockage at the reservoir outlet, thereby inhibiting drainage of the fluid.
Ice blockage may also inhibit drainage of the fluid when the vehicle is parked on an incline. In many instances, a reservoir outlet is disposed at an outer periphery of the reservoir. When the vehicle is parked on an incline, ice blockage may occur at the reservoir outlet, thereby inhibiting drainage of the fluid.